1. Field of the Invention
The present invention relates in general to the biotechnology field and, in particular, to a microplate for assaying samples and methods for making and using such microplates.
2. Description of Related Art
Today biochemical studies associated with growing protein and other biological crystals are carried out on a large scale in both industry and academia, so it is desirable to have an apparatus that allows these studies to be performed in a convenient and inexpensive fashion. Because they are relatively easy to handle and low in cost, microplates are often used for such studies. Microplates typically consist of a matrix of wells formed of a polymeric material. Examples of two traditional sitting drop protein crystallography microplates are briefly discussed below with respect to FIGS. 1 and 2.
Referring to FIGS. 1A and 1B (PRIOR ART), there are respectively illustrated a perspective view and a cross-sectional side view of a traditional microplate 100 manufactured and sold by Hampton Research. As illustrated, the Hampton Research microplate 100 is a 24 well sitting drop microplate that includes an array of twenty-four wells 102, each of which may receive a sample of a protein solution to be assayed.
As seen from the perspective view of FIG. 1A, the Hampton Research microplate 100 includes a frame 104 that supports the wells 102. The frame 104 which is rectangular in shape includes an outer wall 106 and a top planar surface 108 extending between the outer wall 106 and the wells 102. The wells 102 as shown have circular cross-sections in a plane parallel to the top planar surface 108. The outer wall 106 that defines the outer periphery of the frame 104 has a bottom edge 110 that extends below the wells 102. Thus, when the Hampton Research microplate 100 is placed on a support surface, it is supported by the bottom edge 110 with the wells 102 being raised above the support surface to protect them from damage. As illustrated, the outer wall 106 also has a rim 112 to accommodate the skirt of a microplate cover (not shown).
Referring to FIG. 1B, each well 102 includes outer sidewalls 114, a bottom 116 and a post 118. The post 118 located in the center of the well 102 includes a concaved reservoir 120 in which a protein solution and a reagent solution are placed. A portion of the area in the well 102 around the post 118 receives a reagent solution that has a higher concentration than the reagent solution within the concaved reservoir 120. The configuration of the well 102 then enables the protein solution and the reagent solution within the concaved reservoir 120 to interact with the reagent solution around the post 118 via a vapor diffusion process which enables the formation of protein crystals within the concaved reservoir 120. It should be noted the Hampton Research also manufactures and sales a 96 well strip microplate which is similar to the 24 well microplate 100 except that the wells are shrunk down in size.
Referring to FIGS. 2A through 2C (POSSIBLE PRIOR ART), there are respectively illustrated a perspective view, a partial top view and a cross-sectional side view of a traditional microplate 200 manufactured and sold by C. A. Greiner & Sohne Gesellschaft m.b.H. Basically, the Greiner microplate 200 is a 96 well sitting drop microplate where each well 202 may receive up to three samples of protein solutions to be studied. As seen from the perspective view of FIG. 2A, the Greiner microplate 200 includes a frame 204 that supports the wells 202. The frame 204 which is rectangular in shape includes an outer wall 206 that defines the periphery of the frame 204 and a top planar surface 208 extending between the outer wall 206 and the wells 202. The wells 202 as shown have rectangular cross-sections in a plane parallel to the top planar surface 208.
Referring to FIG. 2B and 2C, each well 202 includes a relatively large reservoir 214 and three relatively small reservoirs 216. Each small reservoir 216 includes a flat bottom 218 on which there is deposited a protein solution and a reagent solution. The large reservoir 214 located next to the small reservoirs 216 receives a reagent solution that has a higher concentration than the reagent solutions within the small reservoirs 216. The configuration of the well 202 then enables the protein solution and the reagent solution within each of the small reservoirs 216 to interact with the reagent solution within the large reservoir 214 via a vapor diffusion process which enables the formation of protein crystals within each of the small reservoirs 216.
Unfortunately, the traditional microplates 100 and 200 have many disadvantages attributable to their configurations and their materials of construction such that they are not well suited for protein crystallography studies. For instance, the traditional microplates 100 and 200 are not configured and sized to be handled by a robotic handling system and liquid handling system. Accordingly, there is a need for a microplate that is designed to enable a researcher to effectively conduct protein crystallography studies. This need and other needs are satisfied by the microplate and the methods of the present invention.